Apart from having a well crafted message, a quality mailing depends on its deliverability (i.e. ability to avoid spam filters.) Deliverability depends on the reputation of the sender, a condition that can be measured, managed and improved.
How is reputation measured?
The Reputation index is an internal proprietary algorithm that takes into account several factors like open rate, click rate, bounce rate, etc. which are reported by major providers like Microsoft, Yahoo and Google. This value is calculated every night for every mailing above 1,000 recipients. To access the Reputation index go to the Homepage > List, scroll down to Recent sends section. The value is a % out of 100.
How does a bad reputation impact the sender?
The reputation directly affects inboxing rate (the ability for the messages to reach the "Inbox" as opposed to "Spam" folders) and affects all messages sent from that user's console, regardless of the quality of the messages. Even if there is no direct relationship between a bad reputation and antispam blockers, it is very unlikely a message will be flagged as spam if the reputation is good.
Even if maintaining a good reputation is the main strategy for avoiding spam labeling, creating a quality message is also critical. For example, a message should be void of HTML errors or numeric links (eg. http://64.174.94.10/IMG/LOGO.GIF)
We recommend using the SpamCheck option within Check-Up feature when preparing to send any message.
How to improve the sending reputation?
We recommend following these best practices: